Get value of a property by key, or determine whether a provided object description has a given property.

getProp.js

var expected = window.location.href;
var actual = getProp(window, "location.href");
expected = JSON.stringify(expected);
actual = JSON.stringify(actual);
console.assert(actual === expected, { error: window.location.href });

expected = "default value";
actual = getProp(window, "nothing.expected.here", "default value");
expected = JSON.stringify(expected);
actual = JSON.stringify(actual);
console.assert(actual === expected, { error: "nothing expected…" });

expected = undefined;
actual = getProp({ a: { b: "" } }, "a.b.c");
expected = JSON.stringify(expected);
actual = JSON.stringify(actual);
console.assert(actual === expected, { error: "a.b.c" });

expected = "";
actual = getProp({ a: "" }, "a");
expected = JSON.stringify(expected);
actual = JSON.stringify(actual);
console.assert(actual === expected, { error: "hasOwnProperty???" })

/**
 * Get value for a property described by schema param
 * @param {object} - Dictionary on which to perform validation
 * @param {string} - Pattern to search object's heirarchy
 * @returns {*} - Found value or defaultValue if not found in pattern param
 */
function getProp (obj, schema, defaultReturnValue) {
	if (!obj) return defaultReturnValue;
	const expectedKeyArr = schema.split(".");

	while (expectedKeyArr.length) {
		const currentKey = expectedKeyArr.shift();

		if (obj.hasOwnProperty(currentKey)) {
			obj = obj[currentKey];
			continue;

		} else return defaultReturnValue;

	}

	return obj;
	
}

validateObj.js

var expected = true;
var actual = isObjValid(window, "location.href");
console.assert(actual === expected, { error: window.location.href });

expected = false;
actual = isObjValid(window, "nothing.expected.here");
console.assert(actual === expected, { error: "nothing expected…" });

expected = false;
actual = isObjValid({ a: { b: "" } }, "a.b.c");
console.assert(actual === expected, { error: "a.b.c" });

expected = true;
actual = isObjValid({ a: "" }, "a");
console.assert(actual === expected, { error: "hasOwnProperty???" })

/**
 * Determine whether a provided object contains a key
 * @param {object} - Dictionary on which to perform validation
 * @param {string} - Pattern to search object's heirarchy
 * @returns {bool} - Indicates whether object matches provided schema
 * 
 * @example
 * isObjValid(window, "location.href"); // true
 * isObjValid(window, "nothing.expected.here"); // false
 * isObjValid({ a: { b: "" } }, "a.b.c"); // false
 * isObjValid({ a: "" }, "a"); // true
 */
function isObjValid (obj, schema) {
	if (!obj) return false;
	const expectedKeyArr = schema.split(".");

	while (expectedKeyArr.length) {
		let currentKey = expectedKeyArr.shift();

		if (obj.hasOwnProperty(currentKey)) {
			obj = obj[currentKey];
			continue;

		} else return false;

	}

	return true;
	
}